Samuel e



UNITED STATES SAMUEL E. FOSTER, OF FITCHBURG', MASSACHUSETTS, ASSIGNOR TO HIMSELF AND HENRY F. COGGSHALL, OF SAME PLACE.

FUPLNACE.

Specification forming part of Letters Patent No. 4%@355 dated October '25, 1864.

To all uhom fit 'may (oneri-fn Be it known that I, SAMUEL E. FOSTER, a resident of Fitchburg, in the county of Worcester and State of Massachusetts, have inv vented an Improved Air-Heating Furnace; and I do hereby declare the saine to be fully described in the following speciiication and represented in the accompanying drawings, ot' which- Figure lis a top view, Fig. a front elevation, and Fig. 3 is a vertical section, of it taken through the t'uel'supplyiug throat and epening. Fig. 4 is a vertical section taken through the ash pit door.

My improved air-heatingfurnace is not only canstructed with a close hre-chamber arranged within an air-heating chamber, but has the fuel-throat arranged within the upper part of the air chamber and tire-pot, such iire-potbeing provided with an airinduction pipe and an adjustable valve applied to such pipe, such valve being for the purpose of regulating the admission of air into the fuel, in order to control its combustion. The said furnace also has its grate-bars constructed with teeth or projections within their upper 'surfaces or thereon, and on the sides of such grate-bars, the same being to enable the grate-bars, when moved to and fro longitudinally or laterally, or otherwise, for the purpo ie of causing ashes to fall between them and into the ash-pit, to catch and break or move more or less the coals or clinkers which may rest on the said bars or get between them so as to impede the discharge of ashes from the-ire-pot. Furthermore, in the said furnace the series of grate-bars is arranged in a plane below the top of the ashfpit entrance or throat, and so as to enable a bar or poker, when passed into such throat to be introduced into the lower part of the fire chamber or space directly7 over the grate. Each grate-bar is also con structed with aprojection from its lo wer side to extend down between the two supporting-bars ofthe system of grate-bars, such projection being of a length less than the distance between the said two supportingbars, in order that each grate-bar may be moved lengthwise on its supports and be preserved in position on them. In this furnace the iirepot or chamber, as well as the charge of fuel therein, is to be very large, the fuel,fwhile the furnace may be in use, being consumed by slow combustion, and serving' to heat a very extensive surface of metal to a degree calculated to warm without injuring the surrounding air or rendering it untit for respiration.

In the drawings A denotes the lire chamber or cylinder for holding the fuel. This cylinder is to be a large upright drum of castiron, open at bottom and closed at top, eX- cepting in having in such top a fuel supply opening', a, and a smoke or spent-gas eduction pipe, b, the latter being made to lead out of the interior of the cylinder or tire-chamber, and through the top c of the descending airchamber, I5, which, with its top, may be made ot' brick-work raised on a metallic plate, C, which supports the tire-drum, and separates the air-heating chamber from an ash-pit or chamber, D, arranged below the said drum in manner as shown in the drawings. An air-induction pipe, E, leads into the tire-drum or the ash-pit, and at its outer end is provided with a valve-seat and valve, F, the stem Gr ot' such valve being extended to any convenient position or place for enabling a person to regulate at any time the distance ofthe valve from the seat, and, ot' course, the amount of air passing into the re drum.

The grate-bars of the tire-drum are represented at H H as arranged parallel to each other and supported on two horizontal crossbars, I l, arranged relatively to one another, as shown in I `igs.3 and 4. Fig. 5 is a top view, and Fig. t5 a side view, of one of these grate-bars. It has teeth e e e projecting from its upper side or surface, as well as from each of its sides, and, furthermore, it hasa projection,f, extending down from it, which, when the bar is in place on its supporting-bars, I I, goes between the bars, and is of a length somewhat less than the distance between such bars. Vhile this projection will allow of the grate-bars being lnoved quickly lengthwise on its supports, I I, it will operate to preserve it in place thereon. The purpose of the teeth of the bars has been hereinbefore mentioned.

The series of grate-bars is so arranged with respect to the ash-pit opening Il, which is to y be provided with a door, M, that the plane of i the top surfaces of the several bars shall be somewhat below the top of the said opening L, 1 the arrangement being such as to create an entrance, h, into the lower' part of the fuel-space ofthe fire-drum, through which entrance a bar or a poker maybe introduced for the purpose of stirring up the fuel whenever such may be required. This entrance to the fire chamber or drum is also useful for other purposes.

Air to be warmed in the air-heating chamber is to be led into it by a conduit, N, opening into its lower part, and such air, after having been heated by contact with the outer surface of the redrum, or by heat radiated therefrom, will be discharged from the airchamber by means of one or more eductionpipes o o, leading out of its upper part, such eduction pipe or pipes being carried to such room or apartment in which it may bc desira ble to introduce the heated air. v

The fuel supplying opening a of this furnace leads out ofa sunken space or throat, l), made in the top ofthe brick-work or case t of the airchamber, and bounded, except on the front, by a surrounding partitiomp, which goes down to the top ofthe fire-drum. The said throat enables the fuel to be guided to advantage into the opening of the fire-drum. The said opening, except while the process of charging the fire-drum with fuel may be going on, is t0 be closed by a cover, r.

While the furnace may be in operation it should be kept nearly,if not quite, full of fuel, thev amount thereof periodically consumed being compensated for by a like amount ot' fresh fuel, subsequently introduced into the opening at the top of the furnace.

Each of the grate bars has a hole, s, made through it near its front end, the same being to admit ahooked rod to be inserted within such hole for th-epurpose of enabling a person, by means of such rod, to so move the grate-bar on its supports as to effect the discharge of ashes from the fire-drum into the ash'pit.

I claim as my inventionl. In the a-ir-heatin g furnace or hre-drum and the surrounding air-heating chamber having the fuelthroat arranged. Within the top ofthe air chamber, and with respect to the fuelv opening of the top ofthe hre-drum, substanN tially as specied, and the ash-pit or tire drum provided with an air-i nduction pi pe anda valve thereto, as explained.

2. The described arrangcmeut'of the grade with respect to the doorway or throat ot the ash pit or chamber.

3. The construction of each grate-bar with a bottom proiection, f, having alength so much less than the, distance between the supporting l barsas may be necessary to allow of the gratebar being moved longitudinally back and forth on its supports sufficiently for the purpose of causing the ashes to be discharged from the fire drum and between the gra te bars. Witnesses: SAMUEL E. FOSTER.

lt. H. EDDY, F. P. HALE. Jr. 

